1. Field of the Invention
The present invention relates generally to an organic light emitting diode display and a method of manufacturing the same, and more particularly, to an organic light emitting diode display which broadens a driving range of a gate voltage applied to a driving transistor so as to display a lot of grayscales.
2. Description of the Related Art
An organic light emitting diode display includes two electrodes and an organic emission layer interposed therebetween. Electrons injected from a cathode that is one electrode and holes injected from an anode that is another electrode are bonded to each other in the organic emission layer to form an exciton, and light is emitted while the exciton discharges energy.
The organic light emitting diode display includes a plurality of pixels including an organic light emitting diode that is formed of a cathode, an anode and an organic emission layer, and a plurality of transistors and capacitors for driving the organic light emitting diode are formed in each pixel. A plurality of transistors basically includes a switching transistor and a driving transistor.
When light emitted from the organic light emitting diode is displayed so as to have a range from a black color to a white color according to a driving current Id flowing through the organic light emitting diode, an interval between a gate voltage displaying the black color and a gate voltage displaying the white color is defined as a driving range of the gate voltage. The higher the resolution of the organic light emitting diode display is, the lower the size of one pixel is, and thus, an amount of flowing current per the pixel is reduced, such that a driving range of a gate voltage applied to a gate electrode of the switching transistor and the driving transistor becomes narrow. Accordingly, it is difficult to adjust the magnitude of the gate voltage Vgs applied to the driving transistor so as to ensure a lot of grayscales.
The above information disclosed in this Background section is only for enhancement of an understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.